Referring to FIG. 1, a conventional waterproof container 1 includes an inner foam layer 11, an outer bag 12 surrounding the inner foam layer 11, a cover 13 connected to a top end of the outer bag 12 and covering the outer bag 12, a foam pad 14 enclosed in the cover 13, and a zipper 15 interconnecting the outer bag 12 and the cover 13. The inner foam layer 11 and the foam pad 14 provide thermal insulation and prevent water from entering or exiting the waterproof container 1. However, since the inner foam layer 11 and the foam pad 14 are not fixedly connected, and since the inner foam layer 11, the outer bag 12, the cover 13 and the foam pad 14 are all made of soft and pliable materials, the conventional waterproof container 1 is susceptible to deform when an external force is exerted thereon, and a gap may be formed between the outer bag 12 and the cover 13. As a result, entry of water into the conventional waterproof container 1, and entry of heat into or dissipation of heat out of the conventional waterproof container 1 may occur through the gap or when the zipper 15 is unzipped, thereby adversely affecting the thermal insulation and waterproof properties of the conventional waterproof container 1. Moreover, since the zipper 15 surrounds the top end of the outer bag 12 for interconnecting the outer bag 12 and the cover 13, the zipper 15 may get stuck at corners of the outer bag 12 during a zipping or unzipping process, thereby resulting in inconvenience of users when using the conventional waterproof container 1. In addition, the zipper 15 may partially break off after a number of zipping and unzipping actions.